Hewlett Packard Enterprise HPE XP7, User Manual, Page: 28 / 311

Removing Fast Snap snapshot groups on page 130
Pair tasks using RAID Manager or Remote Web Console on page 194
Methods of storing snapshot data
In the CAW method, writing the P-VOL snapshot data changes the status to “write completion”. In the
COW method, storing the P-VOL snapshot data changes the status to "write completion". The CAW
method wait time is shorter than that of the COW method.
Workflow for the CAW method
The following workflow describes the CAW method and how an XP7 Storage system stores snapshot
data:
1. The host writes data to a P-VOL.
2. The storage system returns the write completion status to the host.
3. The storage system stores snapshot data for the P-VOL in the background.
The following figure illustrates the CAW method.
Workflow for the COW method
The following workflow describes the COW method and how an XP7 Storage system stores snapshot
data:
1. The host writes data to a P-VOL.
2. The storage system stores snapshot data for the P-VOL.
3. The storage system returns the write completion status to the host.
The following figure illustrates the COW method.
28 Methods of storing snapshot data